There are 2 primary categories of surveillance: passive and Energetic. Passive surveillance depends on health treatment companions to report health conditions and disorders to DPH. While this process is simple and cheap, it might be constrained by incompleteness of reporting depending on participation and variability in knowledge top quality. Links https://sergiorxch95284.scrappingwiki.com/857527/die_rolle_der_immobilienmakler_in_fr%C3%B6ndenberg_ein_blick_hinter_die_kulissen